Xie He <xie.he.0...@gmail.com> writes: > The HDLC device is not actually prepending any header when it is used > with this driver. When the PVC device has prepended its header and > handed over the skb to the HDLC device, the HDLC device just hands it > over to the hardware driver for transmission without prepending any > header.
That's correct. IIRC: - Cisco and PPP modes add 4 bytes - Frame Relay adds 4 (specific protocols - mostly IPv4) or 10 (general case) bytes. There is that pvcX->hdlcX transition which adds nothing (the header is already in place when the packet leaves pvcX device). - Raw mode adds nothing (IPv4 only, though it could be modified for both IPv4/v6 easily) - Ethernet (hdlc_raw_eth.c) adds normal Ethernet header. (I had been "unplugged" for some time). -- Krzysztof Halasa Sieć Badawcza Łukasiewicz Przemysłowy Instytut Automatyki i Pomiarów PIAP Al. Jerozolimskie 202, 02-486 Warszawa
